1. Field of the Invention
The present invention relates to a light emitting diode (LED) assembly and a power supply circuit thereof, and more particularly to an LED assembly having an improved power supply circuit which incorporates a snubber circuit therein for smoothing a varied degree of a voltage value of a DC initially input into the LED assembly.
2. Description of Related Art
LED have been available since the early 1960's. Because of the relatively high efficiency of LEDs, nowadays LED usage has been increased in popularity in a variety of applications, e.g., residential, traffic, commercial, industrial settings. The LEDs are often incorporated into a single lamp for achieving sufficient light output.
Conventionally, a power source is connected to the LED lamp to provide current for the LED lamp. Since the power source used for civil lighting purpose has a large voltage, i.e., 120V or 220V, which exceeds a maximum permitted voltage of the LEDs of the LED lamp, a power supply circuit is required to be connected between the power source and the LED lamp for reducing such a large voltage to a suitable voltage, to thereby protect the LEDs from damage by the large voltage. In addition, since the power source provided by the household outlets is alternating current (AC), a converter is needed which converts the alternating current into direct current (DC) first and then supplies the direct current to the LEDs. Thus, the power supply circuit should be devised to have a function of converting the alternating current into the direct current, as well as reducing the high voltage to a low voltage.
However, for such a power supply circuit, it cannot provide the DC with a smoothly gradually increased voltage value initially supplied to the LEDs. As soon as the LED lamp is turned on, the voltage value of the DC input into the LED lamp varies dramatically from zero to a predetermined value in a relatively short time. Such dramatically varied voltage value of the DC input into the LEDs of the LED lamp may cause damage to the LEDs and accordingly significantly reduce a life span of the LEDs. Even worse, the sharp rise of the voltage value of the inputted DC to the LEDs may destroy the LEDs unexpectedly.
What is needed, therefore, is an LED assembly and an improved power supply circuit thereof which can overcome the above-mentioned disadvantages.